Apparatus for recording electric currents produced by living organisms



P. DUCHOSAL Oct. 27, 1931. v

v APPARATUS FOR RECORDING ELECTRIC CURRENTS PRODUCED BY LIVING ORGANISMS Filed Jan. 10, 1930 INVENTOR .puchasaJ p H QmMpW ATTORNEY f Patented Oct; 27, 1931 M UNITED STATES PAT P-QFFICET PIERRE nucnosan,

OF PENNY-VILLAGE, SWITZERLAND, ASSIGNOR OF ONE-HALF TO 7 ROBERT LUTHI, 0F GENEVA, SWITZERLAND APPARATUS vFOCR, RECORDING ELECTRIC CURRENTS PRODUCED BY LIVING OBGANISHB' Application filed January 10, 1930, Serial No. 419,997, and in Switzerland January 12-, 1929.

This invention relates to an apparatus for recording electriccurrents produced byliving organisms and has as its object to provide such an apparatus which is particularly adapted to'be used as an electrocardiographfor recording electric currents which are produced by the heart;

I The invention consists in an apparatus comprising a polarizer having terminals which are connected with electrodes adapted tocome in contact with the-subject of which the currents are to be recorded, a ticker, an amplifier having triode lamps, a rectifying device, and an oscillograph by means of which the currents are recorded.

In the drawings,

Figure 1 is a general diagrammatic view of the recording apparatus.

' 1 Figures 2 to 8 show diagrams of the successive variations of the electric current passing through the apparatus.

Figures 9 and 10 show two modifications of a ticker. a

Figure 11 shows an inking device of a recorder.

The apparatus comprises a polarizer 1 adapted to compensate a constant part of the current, in order to permit the amplifier 2 and the oscillograph 3 to function with maximum sensibility with the variable remainder of the current. The polarizer comprises a potentiometer 4 with continuous variation, 'a cell 5 and two resistances 6. This whole device is enclosed in a common casing which is grounded. The polarizer 1 is connected to the vibrating blade 8 of an electric excitation ticker 9 means of a conductor 7. The blade 8 is provlded with a platinized contact 8' adapt ed to make contact with the end of a contact screw 10. The blade 8 is made to vibrate by means of an 'electromagnet 11 adapted to be traversed by an alternating current which is produced by two triode lamps 12 mounted to produce an oscillating circuit. This device is also enclosed in a casing.

The ticker 9 is used to split up the electric current which is to be amplified and is connected by means of a conductor 13 with the low frequency transformer containing'amplifier 2 of a type whichis employed in wireless installations. This amplifier can have three or four amplification stages, each stage being separately enclosed and the tension of polarization of the screen grid of the last nected by means of a condenser 14a to the I last lamps 14: of the amplifier, the screen grid of the lamp 15 being connected by means of a resistance 15a to the positive terminal of a heating battery which is not represented.

The current which is furnished by the triode lamp 15 flows through a filter 16 before coming to the oscillograph 3. The filter may consist of a capacity in parallel and resistances in series and may be substituted by an interrupting device when the 'frequency of. the current is high enough.

The oscillograph 3 of an electro-magnetic type, comprising a stylus 26, records the current, which is' taken, up by the electrodes 17, on a paper surrounding" the drum 18, the electrodes consisting as usual of vdamp bands.

The recording can be made by means of an inking stylus on white paper or by a simple stylus tracing a line on blackened paper.

The described installation is grounded as shown at 19. v

The operation of the apparatus will now be described with reference to the diagrams shown in Figures 2 to 8. The diagrams of Figure 2 represents the weak biological current with slow variations which is to be rev corded. After having passed the polarizer 1 the. current will be reduced to near zero as shown in' Figure 3. After leaving'th'e ticker the current is as represented by Figure 4. Following the first transformer and in the entire amplifier 2 the current takes the a shape as shown in Figures 5 or 6. The diagram of Figure 7 represents the current after leaving the detector 15 and the diagram of Figure 8 shows the current after having passed the filter 16.

Instead of employing an electric excitation source of direct current.

ticker as represented in Figure 1, there can be used a rotary ticker driven by a clockwork as shown in Figure 9. This ticker comprises a cylinder 21 of insulating material and provided with metallic bars 22 upon which a resilient blade 23 is adapted to rub. Terminals 24 and 25 are provided for connection of the ticker with the amplifier 2 and with the polarizer.

There'could also be used a ticker as shown in Figure 10. This ticker comprises an elec tromagnet 39 acting upon an armature 27 which is formed by a flexible blade having the same period of oscillationas the vibrating blade 8 and being connected with this blade by means of an insulating piece 28 consisting for instance of an ebonite bar or an ordinary string. 29 is a contact which cooperates with the armature 27, and 30 and 31 indicate two terminals for connection with the poles of a flows through the circuit of the'electro-magnet 39, the armature 27 starts to vibrate. like the hammer of an electric bell and transmits its movement by means of the insulating piece 28 to the blade 8. The two blades 27 and 8 have to be placed at a certain dis-' tance from each other in order that the current flowing through the interrupter 8, 8, 10 is not subjected to magnetic influences arising from the electromagnet 39. Preferably the electro-magnet 39 and itsarmature 27 are-enclosed in an iron casing while the vibrating blade 8 and the parts related therewith are enclosed in a zinc casing.

Figure 11 illustrates a recording device which can be used in place of the stylus 26 shown diagrammatically in Figure 1. This recording device comprises aglass tube 32 with a curved end 33. The 0 posite end is held in a rubber tube 34 whic is attached to the connecting piece 35. An ink reservoir touches the paper, this latter sucks the ink andv produces a regular flow in the tube 32. This ink recording device could also be replaced by an optical galvanometer permitting a photographic recording of the current.

I claim 1. An apparatus for recording electric currents produced by living organisms, comprising a polarizer provided with terminals, electrodes adapted to make contact with the organism-of which the currents are to be recorded and to be connected with said terminals, an electromagnet, a ticker having 8. vii brating blade, a second vibrating blade having the same period of oscillation as said first When a current trodes adapted to make contact with the organism of which the currents have to be recorded and to be connected with said terminals, a ticker adapted to transform the currents produced by the organism into high fre quency alternating current, an amplifier for amplifying said high frequency currents, a rectifying device, and an oscillograph adapted to record the currents after leaving said rectifyingdevice.

In testimony whereof I afiix my signature.

PIERRE DUCHOSAL. 

